package cn.zf233.xcloud.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.ThreadPoolExecutor;

/**
 * Created by zf233 on 2020/11/4
 */
@Configuration
@EnableAsync
public class ExecutorConfig {

    private static final int corePoolSize = 64;           // 核心线程数（默认线程数）线程池创建时候初始化的线程数
    private static final int maxPoolSize = 128;            // 最大线程数 线程池最大的线程数，只有在缓冲队列满了之后才会申请超过核心线程数的线程
    private static final int keepAliveTime = 60;          // 允许线程空闲时间（单位：默认为秒）当超过了核心线程之外的线程在空闲时间到达之后会被销毁
    private static final int queueCapacity = 32;          // 缓冲队列数 用来缓冲执行任务的队列
    private static final String threadNamePrefix = "Async-Service-"; // 线程池名前缀 方便我们定位处理任务所在的线程池

    @Bean
    public ThreadPoolTaskExecutor taskExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();

        executor.setCorePoolSize(corePoolSize);
        executor.setMaxPoolSize(maxPoolSize);
        executor.setQueueCapacity(queueCapacity);
        executor.setKeepAliveSeconds(keepAliveTime);
        executor.setThreadNamePrefix(threadNamePrefix);
        // 线程池对拒绝任务的处理策略 采用了CallerRunsPolicy策略，当线程池没有处理能力的时候，该策略会直接在 execute 方法的调用线程中运行被拒绝的任务；如果执行程序已关闭，则会丢弃该任务
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        // 初始化
        executor.initialize();

        return executor;
    }
}
